Process of treating coal



Patented Sept. 29, 1925.

UNITED STATES JOHN F. LAI-IART, OF MINNEAPOLIS, MINNESOTA.

PROCESS or TREATING coAL.

No Drawing.

To all whom it may concern:

Be it known that I, JOHN F. Larmn'r, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Processes of Treating Coal; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention provides an improved means for treating coal, to wit: anthracite, bituminous, and lignite coals, with a commingled material, which increases the completeness of combustion and results in the development of greater heat energy and in elimination or great reduction of the smoke nuisance, all of which contribute to a greater economy in the use of fuel.

Softcoal and especially lignite coal tend to disintegrate in the initial process of combastion and thus to produce waste by creating gases that are carried out of the furnace before they can be completely consumed. The liner the coal, the greater is the tendency for the above waste action to take place.

In carrying out my invention, I first produce a dry powdered mixture of lime, (preferably unslacked or quick lime), calcium oxide, (CaO), common salt, (NaCl), and Portland cement, (this designation being used in its generally accepted broad sense). This finely divided or powdered mixture is thoroughly commingled with the coal particles and will adhere to the exterior thereof. I have obtained the best results by mixing the above ingredients in the proportions of fifteen percent salt, twenty-five percent unslacked lime, and sixty percent Portland cement, but good results can be obtained by using from ten to twenty percent of salt, from fifteen to thirtyfive percent of lime, and from forty to seventy percent of Portland cement. Also, I advisably use about forty pounds of the above mixture to one ton of coal, but the amount of such mixture used will depend somewhat upon the character of the coal and frequently varies from twenty-five to fifty pounds per ton of coal. Fine coal can advantageously contain a larger amount of the said mixture than larger coal.

The powdered mixture will adhere to the exterior of the coal particles and will form a coating thereon. The unslacked lime will Application filed February 7, 1324. Serial No. 691,287.

absorb certain of the oils in the coal and some of the moisture from the coal and, by such action, will become more or less slacked, and for this reason, it is advisable to apply the mixture to the coal a reasonably short time beforethe coal is to be burned. It may not be possible to state with absolute certainty just the manner in which the several ingredients operate to improve the combustion of the coal, but I have demonstrated by practice that it does accomplish the desired results herein stated. Observation and experiments indicate that the cement and lime draw more or less of the. oil from the coal to the surface where they will be burned evenly and rapidly and the coal particles will be held in form while they are being consumed.

To sum up, the treatment of the coal as described tends to prevent disintegration of the coal when exposed to the atmosphere and prevents too rapid disintegration thereof when being burned; the coal is made more highly and completely combustible; the flames produced in burning of the coal will be more intense; the tendency to produce clinkers is nearly or quite eliminated; the oil contents of any steam coal or screenings are more quickly and completely burned; the production of smoke is eliminated or re duced to a minimum; and the, greatest possible heating efiiciency is obtained from any particular kind of coal. In practice, I have found that the finest grade of screenings, when treated by the above process or with the above mixture, will be burned in the most satisfactory manner and that the burning action of all grades of coal will be improved by such treatment. The condition of lignite will be so greatly improved by the treatment that it may be used as a substitute for. better grades of coal and in places where untreated lignite cannot be used.

W hat I claim is:

1. The process of treating coal which consists in commingling common salt, unslacked lime, and Portland cement, in proportions of from ten to twenty percent of salt, fifteen to thirty-five percent of lime, and forty to seventy percent of Portland cement, and in cominingling said mixture with the coal particles in the proportion of from twenty-five to fifty pounds of such mixture to one ton of coal.

2. As a new product, coal particles externally treated with a dry mixture of common salt, lime, and Portland cement, the said mixture heingapplied to the coal in the proportion of from twenty-five to fifty pounds thereof to one ton of coal, and the said mixture itself containing from ten to-twenty percent of salt, fifteen to thirty-five percent of lime, and from forty to seventy percent of Portland cement.

3. As a new product, coal particles exter- 10 nally treated with adry mixture of common salt, unslacked lime, and Portland cement, the said-mixture being applied to the coal in the proportion of from twenty-five t0 fifty pounds thereof to one ton of coal, and the said mixture itself-containing from ten to twenty percent of salt, fifteen to thirty five percent o f unslacked lime, and from forty to seventy percent of Portland cement.

In testimony whereof I aflix my signature.

JOHN F. LAHART. 

